1. Field of the Invention
The present invention relates to a weld nut and, more particularly, to a weld nut which has a nut and a base panel mounted securely with the nut to improve a hardness and a weldability of the weld nut.
2. Description of Related Art
With reference to FIGS. 8 and 9, a conventional weld nut (50) in accordance with the prior art has a diameter, a bottom, a threaded hole and multiple weld points (51). The threaded hole is formed through the weld nut(50). The weld points (51) are formed on and protrude from the bottom of the weld nut (50) around the threaded hole at intervals to be welded on a workpiece and to securely mount the weld nut (50) on the workpiece. The weld points (51) are preferable to have a carbon content less than 25% to raise a weldability of the weld nut(50) being welded on the workpiece. With being welded on a workpiece, the weld nut (50) does not cause vibrations during screwing a bolt onto the weld nut (50). Additionally, the weld nut (50) remains engaged securely with the workpiece and does not detach from the workpiece even when a huge external force strikes onto the workpiece.
However, the weld nut (50) is formed as an integral single piece and has a uniform carbon content. With the carbon content less than 25%, a hardness of the weld nut (50) is insufficient and the weld nut (50) is easily deformed and detached from the workpiece by an external force.
Further, each interval between adjacent weld points (51) is shorter than the diameter of the weld nut (50), and this part on the workpiece will result in brittle destruction on the workpiece due to quench hardening when the weld points (51) are melted for welding.